Average alkyl chain length

The average alkyl chain length found in the different... 

The c.m.c. of nonionic surfactants is about two orders of magnitude lower than the corresponding anionics with the same alkyl chain length. The solubility of the alcohol ethoxylates depends both on the alkyl chain length and the number of ethylene oxide units in the molecule. Molecules with an average alkyl chain length... 

C9-C15 alkyl 3- to 8-mole ethoxylates separation by average alkyl chain length Merck RP-18 F254 75 25 EtOH/HzO Iodine vapor pinacryptol yellow, 366 nm 14... 

Because of its superior solubility characteristics, a high 2-phenyl LAS (with an alkyl chain length average of 11.4) was the preferred type. The detergency performance of one LAS/AE type of formulation was discussed previously (see Figs. 12 and 13). Early commercial heavy-duty liquid (HDL) formulations were built with phosphate, but since 1979 almost all U.S. HDLs have been formulated without phosphate. 

Surfactants elimination via bile is faster in fed than in unfed fish [12,40], due to the higher secretion of bile into the digestive tract when fed. The fastest and slowest surfactants excreted were the linear alkylbenzene sulphonates (C12) and the alkyl sulphates (especially the C12-15) [12], respectively. Depuration of NP is quite rapid, 1.8-20 days in fathead minnows [32] and 4 days in the Atlantic salmon [41]. Within the same organism, differences in tissues were observed, with values of 20 h for adipose tissue and 18.5 h for muscle of rainbow trout [24]. The elimination rate of non-ionic surfactants is directly proportional to the ethoxylate unit number and inversely proportional to the alkyl chain length [33]. Average elimination rates (k2) of NPE02.8 and NP in clams were 1.8 and 1.4 per day, respectively [21], and decreasing k2 values from 0.19 to 0.001 per day were obtained from butylphenol to dodecylphenol in salmon [42]. 

Fraction Wt. % Carbon in Aliphatic Region Unbranched Alkyl-Groups Average Carbon Chain Length ... 

For the polar fraction, the combined n-alkane + 1-alkene yield increased up to 60 min stress time, then reversed (Figure 4). The yield of the larger molecules - 15 carbons and above -was drastically reduced at 180 min. Even at 16 min the products obtained in largest yield were on the low end of the JP-5 distillation range. This was consistent with the lower value found by nmr for the average unbranched alkyl chain length. The aromatic yield pattern fell between that for the saturate and polar fractions. The maximum yield for the aromatic fraction always fell at 10 or 11 carbons with a fairly sharp maximum. 

A comparison of poly(3-alkylthiophene)s (P3ATs) with side chains ranging from butyl (35d) to dodecyl (35g) showed a non-monotonic dependence of field-effect mobility on alkyl chain length (Figure 3.1.13).[11,210] The average mobility varied... 

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